Simplify the following expression: $q = \dfrac{z + 3}{4} \div \dfrac{9z}{5}$
Dividing by an expression is the same as multiplying by its inverse. $q = \dfrac{z + 3}{4} \times \dfrac{5}{9z}$ When multiplying fractions, we multiply the numerators and the denominators. $q = \dfrac{ (z + 3) \times 5 } { 4 \times 9z}$ $q = \dfrac{5z + 15}{36z}$